My Home Ideas

Special Offers

Be the first to know about This Old House contests, sweepstakes, and events and receive special offers and promotions from your favorite home improvement brands. We'll even send you regular reminders to enter our sweepstakes.

Contribute to This Story Below

More in Tools

Plumb Bob

Tie a length of string to a lump of metal and you have a plumb bob, a gravity-powered tool so simple and so accurate that it's survived virtually unchanged since the Egyptians were building pyramids. Use it to transfer marks from ceiling to floor (and vice versa). Or measure how far the string is from a vertical surface: If the measurements are equal top and bottom, the surface is plumb, Bob.